1. Field of the Invention
The present invention relates to an apparatus for automatic playing of a musical instrument, an apparatus that plays music on demand by using prerecorded play information, which is held in a storage device, to control the performance of a musical instrument.
Apparatuses for automatic playing of musical instruments, which are attached to, for example, pianos, are in current, practical use. To produce music, these apparatuses use prerecorded play information to operate drive mechanisms that manipulate keyboards or pedals.
In addition to normal playing functions, presently employed playing apparatuses ordinarily have a function for accelerating musical progression (hereafter referred to as "fast forward"), and another function for accelerating musical retrogradation (hereafter referred to as "fast reverse").
As fast forward and fast reverse differ drastically from normal playing functions, and possess the potential to adversely affect the quality of music, reproduction fidelity demands that special care be taken to ensure that melodic content is not degraded when fast forward and fast reverse are used.
2. Description of the Related Art
A conventional apparatus for automatic playing of a musical instrument incorporates a storage device, e.g., a floppy disk, that holds play information, including, for example, key numbers, key depression force and time information. When the apparatus receives a signal to begin playing, via, for example, an operation panel, it reads play information from the storage device and uses this information in its operation of the musical instrument.
More specifically, play information constituting event information groups is previously stored in a storage device. As shown by the example in FIG. 4, one event information group consists of an identification symbol, a key number, key depression force, and time information.
When playing is initiated, one event information group of the play information is read from the storage device, and the included time information is examined. When the time information corresponds to an execution timing (time) for the read-out event information, procedures for this event are performed, i.e., keys are depressed or released.
After the procedures for one event information group have been completed, the next event information group is read from the storage device, and the described process is repeated. Music is produced by repeatedly reading and processing event information groups.
The execution time for an event information group is determined as follows: A time count, which is held by a time counter that counts clock cycles, is compared with the time information in the read-out event information group, and when they correspond, it is assumed that the procedures for the event should be performed.
Besides the above described normal playing functions, a conventional apparatus for automatic playing of a musical instrument has fast forward and fast reverse functions. There are two well-known methods for performing fast forward or fast reverse that are used when either the fast forward function or the fast reverse function is selected.
To perform fast forward or fast reverse using the first method, the speed of the clock that governs the operation of the time counter is increased to greater than that for normal reproduction. The performance of the time counter is thereby accelerated, and the execution time for the procedures of the current event information group is advanced.
When fast forward or fast reverse is performed using the second method, the clock speed is not increased and the performance of the time counter is not accelerated. Instead, to speed up performance and to determine an advanced execution time, predetermined multiples of the time count held by the time counter are compared with the time information of the most recently read event information group.
As an automatic playing apparatus that includes a drive mechanism cannot adequately cope with high speed execution, and as the directional order of ON events and succeeding OFF events is inverted when fast reverse is performed, such an automatic playing apparatus usually does not activate operation terminals when either fast forward or fast reverse is selected.
More specifically, when fast forward or fast reverse is selected, all operation terminals, which include a keyboard terminal and a pedal terminal that are being driven, are set to OFF, and fast forward or fast reverse is immediately thereafter begun.
After the fast forward or the fast reverse has been completed, and until the next pedal play information is processed, the pedal terminal is maintained in the OFF state, as it was set when the fast forward or the fast reverse was selected.
Suppose, then, that the first pedal play information to be processed after playing is resumed is OFF event information. Although the state of an event must be 0N during the period between the resumption of normal play and the point at which pedal play information is processed, as the pedal terminal has not been activated the actual event state during this period is OFF, and music quality is thereby significantly impaired.
The shortcomings associated with fast forward and fast reverse operations will be explained in more detail referring to FIG. 5 (fast forward phase) and FIG. 6 (fast reverse phase).
FIG. 5 is a diagram for explaining a fast forward operation. Pedal play information is represented by the identifiers e1 to e8. The several intervals between the identifiers e1 to e8 are occupied by keyboard play information, but such information is not shown here.
In the interval between el and e2 a pedal terminal is being driven (ON period), and in the interval between e2 and e3 a pedal terminal is not activated (OFF period). The succeeding ON/OFF states are as shown in the lower level in the diagram.
If fast forward is begun at point A and is released at point B, music is immediately reproduced at point B.
Although the pedal terminal should be activated in the interval between e5 and e6, as shown in FIG. 5, because of the fast forward selection, as described above, the pedal terminal is actually in the OFF state, and music reproduced during this interval is significantly impaired.
FIG. 6 is a diagram for explaining a fast reverse operation. Pedal play information is represented by the identifiers e11 to e18. The several intervals between the identifiers e11 to e18 are occupied by keyboard play information, but such information is not shown here.
In the interval between e11 and e12 the pedal terminal is being driven (ON period), and in the interval between e12 and e13 the pedal terminal is not activated (OFF period). The following ON/OFF states are as shown in the lower level in the diagram.
If normal playing is started at point C and fast reverse is selected at point D, to perform fast reverse, play information is read out toward point E at faster than the normal playing speed. Then, when fast reverse is released at point E, music is immediately reproduced there.
Although the pedal terminal should be activated in the interval between e11 and e12, as shown in FIG. 6, because of the fast reverse selection, as described above, the pedal terminal is actually in the OFF state, and music reproduced during this interval is significantly impaired.
When a pedal terminal is, for example, a damper pedal of a piano, the period during which music is degraded spans several seconds, sometimes several tens of seconds.